Blood

• Blood is considered a connective tissue because it consists of cells surrounded by an extracellular matrix.
• Blood is the only fluid tissue of the body and accounts for 8% of our body weight.

  -5-6L in men/ 4-5L in women
• The color of blood is dependent on oxygen saturation, with dark blood indicating low oxygen levels and bright blood indicating high oxygen levels.
• Blood pH should be between 7.35-7.45.
• Transfusion Reaction is when transferred blood does not match and the immune system responds.
• In a Transfusion Reaction, the donor cells are attacked by the recipient’s plasma agglutinins, causing vessels to clog, rupture and release free hemoglobin into the blood stream.
• Transfusion Reaction can lead to renal failure and death.
• Transfusion is the transfer of whole blood or part of whole blood.
• Blood plasma is the liquid part of blood, making up 55% of blood volume, and consists of 90% water.
• The water in blood plasma acts as a solvent for other substances, with proteins being the majority of these substances.
• Most of the proteins in blood plasma are produced by the liver and are divided into three groups: albumin (60%)- maintain colloid osmotic pressure, globulins (40%)- these are functional proteins such as enzymes or antibodies, and other solutes (<5%).
• Blood viscosity is determined by the amount of red blood cells

  -Hemocrit- percentage of the blood volume that consists of erythrocytes

  -men 47 (+/- 5%)

  -women 42 (+/- 5%)

  The higher the value, the higher the viscosity
• Hemopoiesis or hematopoiesis is the process of blood cell formation, occurring in red bone marrow, where all formed elements start as stem cells (hemocytoblast).
• Erythrocytes are the most numerous cells of blood, making up 5 million per µl of blood, with a bi-concave disc shape and a diameter of about 8 µm.
• The red color of erythrocytes comes from protein hemoglobin, which carries oxygen.
• Erythrocytes have no nucleus or mitochondria, meaning they cannot use the oxygen to generate ATP.
• Erythropoiesis is the process where hemocytoblast transforms into a proerythroblast, develops into a erythroblast, and becomes a reticulocyte, which can already transport oxygen. Becomes erythrocyte after being released into the blood.
• The main function of erythrocytes is the transport of oxygen from the lungs to the tissue, and its function is dependent on hemoglobin (Hb).
• Hemoglobin consists of 4 chains (2 alpha and 2 beta chains)

  -These chains make up the protein (globin) part of the molecules

  -The heme-part comes from a pigment (heme) that contains one atom of iron
• Each of these molecules can carry 4 O2 molecules, with loading occurring in the lungs.
• Oxygenation (oxyhemoglobin) results in bright blood when O2 is loaded, while deoxyhemoglobin results in dark blood when O2 is unloaded.
• Hemostasis: Coagulation Step 2, known as the Prothrombin Activator (Prothrombinase), catalyzes the transformation of prothrombin to thrombin.
• Coagulation has three steps and several factors are involved.
• Coagulation, also known as clotting, is a set of reactions that lead to the formation of an insoluble fibrin and gel-like blood clot.
• Hemostasis: Coagulation Step 1: Intrinsic Pathway- activated by platelets, platelets activate coagulation factors and release platelet factor 3 (PF3). Extrinsic Pathway- this is triggered by the release of tissue factor (TF) due to damage of the vessel, also uses platelet factor 3, much faster.
• Aspirin blocks thromboxane, Coumadin/Warfarin blocks Vitamin k, and TPA breaks down clot, improving blood flow.
• Rh Factor is a system with many antigens but only three are common (C, D and E), with D being the only one of clinical importance.
• Rh+ or Rh- refers to the presence or absence of antibodies against Rh antigens, which are only formed after exposure (during birth or via transfusion).
• Rh Factor antibodies can cross the placenta during pregnancy and attach the RBCs of the baby, leading to Hemolytic Disease of a Newborn or Erythroblastosis Fetalis.
• RhoGAM is a medication used to prevent the baby from being sensitized.
• Disorders of Hemostasis include Thromboembolic Disorders, where a clot forms in an unbroken vessel (thrombus), Embolus, where a piece of clot breaks off, and Embolism, where a piece of clot gets lodged in an artery (either pulmonary or systemic).
• Hemo stasis: Coagulation Step 3, known as Thrombin, converts soluble fibrinogen into insoluble fibrin.
• Hemophilia is a condition where there is a lack of clotting factors.
• Fibrinolysis is the enzymatic breakdown of clot within a few days.
• Hepatitis and liver disease can decrease clotting factors.
• Serum containing antibodies can be given to mothers to prevent the baby from being sensitized.
• Hemo stasis: Coagulation Step 1 uses platelet factor 3 (PF3) and is much faster, skipping steps.
• The ABO System is based on the presence or absence of substances (antigens) on the plasma membrane of the RBC.
• The heme group can also bind to other gases, such as CO2, forming carbaminohemoglobin.
• Normal values for hemoglobin are 16 (± 2) in men and 14 (±2) in women.